Evolution of starfishes: Morphology, molecules, development, and paleobiology. Introduction to the symposium

Among starfishes, fascinating life cycles and complex morphological pattern s have evolved within a familiar but unusual basic body plan. In spite of t hese rich complexities, available phylogenetic interpretations conflict, an d the history of this important group remains uncertain. The symposium brou ght together current perspectives on phylogeny, the implications of certain poorly known aspects of asteroid morphology, and consideration of signific ant events that preceded the diversification of extant asteroid groups in t he Mesozoic, It has become axiomatic in modern organismal biology that strongly supporte d phylogenetic reconstructions are crucial to the understanding of biologic al pattern and progress, Although asteroids exhibit complex morphologies, l ife cycles, and behaviors that indicate their status as ideal model organis ms in the study of marine Invertebrates, their evolutionary history remains obscure. This is in part due to a lack of treatment by researchers but als o in part due to inherent limitations of the available data, In the following pages, the state of inquiry into the study of relationship s among starfishes is arranged in three sections: the nature of the fossil record tan introduction to modern starfishes), taxa and morphology, and phy logenetic interpretations.